id<\/strong>: 5\r\n};<\/pre>\n\u305d\u3057\u3066\u3053\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u30eb\u30fc\u30d7\u3067\u5168\u3066\u53d6\u308a\u51fa\u3059\u5834\u5408\u3092\u8003\u3048\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
for(let key in mixObj) {\r\n\r\n console.log(key);\r\n\r\n}<\/pre>\n\u3053\u306e\u5834\u5408\u3001\u30ad\u30fc\u306f\u3069\u3093\u306a\u9806\u756a\u3067\u53d6\u5f97\u3067\u304d\u308b\u3067\u3057\u3087\u3046\u304b\u3002<\/p>\n
\u304a\u305d\u3089\u304f\u30b3\u30fc\u30c9\u3067\u66f8\u3044\u305f\u3068\u304a\u308a\u300cname\u300d\u300c1\u300d\u300cid\u300d\u306e\u9806\u756a\u306b\u306a\u308b\u3068\u601d\u3046\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u304c\u3001\u5b9f\u969b\u306f\u305d\u3046\u306f\u306a\u308a\u307e\u305b\u3093\u3002<\/strong><\/p>\n\u306a\u3093\u3068\u3001\u6b21\u306e\u3088\u3046\u306b\u300c\uff11\u300d\u304c\u5148\u982d\u306b\u304d\u3066\u3057\u307e\u3044\u307e\u3059\u3002<\/p>\n
\n- 1<\/li>\n
- name<\/li>\n
- id<\/li>\n<\/ul>\n
\u3064\u307e\u308a\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306f\u30c7\u30fc\u30bf\u306e\u9806\u756a\u3092\u4fdd\u8a3c\u3057\u3066\u3044\u306a\u3044<\/strong>\u306e\u3067\u3001\u3082\u3057\u9806\u756a\u304c\u91cd\u8981\u306a\u5834\u5408\u306f\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u4f7f\u3046\u3079\u304d\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/strong><\/p>\n\u3067\u306f\u3001\u3069\u306e\u3088\u3046\u306b\u3059\u308b\u304b\u3068\u3044\u3046\u3068\u7b54\u3048\u306f\u300c\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u300d\uff08\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u914d\u5217\uff09\u3067\u3059\u3002<\/strong><\/p>\n\u5b9f\u969b\u306e\u4f8b\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
\/\/ \u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3067\u5b9a\u7fa9\r\nconst collection = [<\/strong>\r\n { key: 'name', value: '\u592a\u90ce' },<\/strong>\r\n { key: 1, value: 'ONE' },<\/strong>\r\n { key: 'id', value: 5 },<\/strong>\r\n]<\/strong>;\r\n\r\nfor(let i in collection) {\r\n\r\n const data = collection[i];\r\n console.log(data.key<\/strong>); \/\/ \ud83d\udc48 \u9806\u756a\u306f\u305d\u306e\u307e\u307e\u4fdd\u6301\u3055\u308c\u307e\u3059<\/strong>\r\n\r\n}<\/pre>\n\u3053\u306e\u3088\u3046\u306b\u30c7\u30fc\u30bf\u3092\u914d\u5217\u5316\u3059\u308b\u3053\u3068\u3067\u30eb\u30fc\u30d7\u306e\u9806\u756a\u3092\u56fa\u5b9a\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n
\u3010\u30cf\u30de\u30ea\u5ea6\u3011 \ud83d\ude2b\ud83d\ude2b<\/p>\n
for ~ of \u306b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306f\u4f7f\u3048\u306a\u3044<\/h1>\n
ES 6<\/code> \u306e\u65b0\u3057\u3044\u66f8\u304d\u65b9\u306bfor ~ of<\/code>\u3068\u3044\u3046\u306e\u304c\u3042\u308a\u307e\u3059\u3002
\n\u3053\u308c\u306f\u3001\u5024\u3092\u3072\u3068\u3064\u305a\u3064\u30eb\u30fc\u30d7\u3067\u53d6\u5f97\u3067\u304d\u308b\u66f8\u304d\u65b9\u306a\u306e\u3067\u3059\u304c\u3001\u5b9f\u306f\u3053\u308c\u306b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306f\u4f7f\u3048\u307e\u305b\u3093\u3002<\/p>\n\u5b9f\u969b\u306e\u4f8b\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
\/\/ \u26a0\u3053\u308c\u306f\u9593\u9055\u3063\u305f\u4f8b\u3067\u3059<\/strong>\r\n\r\nconst alcohol = {\r\n beer: '\u30d3\u30fc\u30eb',\r\n wine: '\u30ef\u30a4\u30f3',\r\n cocktail: '\u30ab\u30af\u30c6\u30eb'\r\n};\r\n\r\nfor(let value of alcohol)<\/strong> { \/\/ \ud83d\udc48 \u30a8\u30e9\u30fc\u306b\u306a\u308b<\/strong>\r\n\r\n \/\/\r\n\r\n}<\/pre>\n\u3053\u308c\u306f\u4e00\u898b\u3046\u307e\u304f\u3044\u304d\u305d\u3046\u3067\u3059\u304c\u3001\u4ee5\u4e0b\u306e\u30a8\u30e9\u30fc\u304c\u51fa\u307e\u3059\u3002<\/p>\n
Uncaught TypeError: alcohol is not iterable<\/strong><\/pre>\n\u610f\u5473\u3068\u3057\u3066\u306f\u3001\u300c\u305d\u306e\u30c7\u30fc\u30bf\u306f\u30eb\u30fc\u30d7\u3067\u304d\u306a\u3044\u3088\ud83d\ude2b<\/strong>\u300d\u3068\u3044\u3046\u3082\u306e\u3067\u3059\u3002<\/p>\n\u3067\u306f\u3001\u3069\u3046\u3059\u308b\u304b\u3068\u3044\u3046\u3068\u6b21\u306e\u3088\u3046\u306bObject.entries()<\/code>\u3067key<\/code>\u3068value<\/code>\u306b\u5206\u5272\u3057\u306a\u304c\u3089\u30eb\u30fc\u30d7\u3092\u3057\u307e\u3059\u3002<\/p>\nfor(const [key, value] of Object.entries(alcohol)) {<\/strong>\r\n\r\n console.log(key, value);\r\n\r\n}<\/pre>\n\u306a\u304a\u3001for ~ in<\/code>\u3067\u30ad\u30fc\u3092\u53d6\u5f97\u3057\u306a\u304c\u3089\u30eb\u30fc\u30d7\u3059\u308b\u5f93\u6765\u306e\u65b9\u6cd5\u3082\u4f7f\u3048\u307e\u3059\u3002<\/p>\nfor(let key in alcohol) {<\/strong>\r\n\r\n const value = alcohol[key];\r\n console.log(key, value);\r\n\r\n}<\/pre>\n\u3010\u30cf\u30de\u30ea\u5ea6\u3011 \ud83d\ude2b\ud83d\ude2b\ud83d\ude2b<\/p>\n
replace() \u306f\u57fa\u672c\u7684\u306b\u3072\u3068\u3064\u3060\u3051\u3057\u304b\u5165\u308c\u66ff\u3048\u3066\u304f\u308c\u306a\u3044<\/h1>\n
\u4f8b\u3048\u3070\u3001\u6b21\u306e\u3088\u3046\u306a\u6587\u5b57\u5217\u306e\u4e2d\u304b\u30891<\/code>\u3092_one_<\/code>\u306b\u5165\u308c\u66ff\u3048\u308b\u5834\u5408\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\nconst text = '123123123';<\/pre>\nJavaScript<\/code>\u306b\u306f\u3001replace()<\/code>\u3068\u3044\u3046\u30e1\u30bd\u30c3\u30c9\u3092\u304c\u3042\u308b\u306e\u3067\u3053\u308c\u3092\u4f7f\u3063\u3066\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u6b63\u898f\u8868\u73fe\u3067\u5165\u308c\u66ff\u3048\u3092\u3057\u307e\u3059\u3002<\/p>\nconst text = '123123123';\r\nconst text2 = text.replace(\/1\/, '_ONE_');<\/strong><\/pre>\n\u3057\u304b\u3057\u3001\u3053\u3053\u306f\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n
\u306a\u305c\u306a\u3089\u3001JavaScript\u306e replace() \u304c\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u306e\u306f\u3001\u901a\u5e38\u306f\u6700\u521d\u306e\uff11\u30f6\u6240\u3060\u3051<\/strong>\u3060\u304b\u3089\u3067\u3059\u3002<\/p>\n\u3064\u307e\u308a\u3001text2<\/code>\u306f\u300c_ONE_23123123<\/strong>\u300d\u3068\u306a\u308a\u307e\u3059\u3002<\/p>\n\u3067\u306f\u3069\u3046\u3059\u308b\u304b\u3068\u3044\u3046\u3068\u3001\u6b63\u898f\u8868\u73fe\u306bg<\/code>\u3092\u3064\u3051\u3066\u3042\u3052\u308b\u3053\u3068\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\nconst text = '123123123';\r\nconst text2 = text.replace(\/1\/g<\/strong>, '_ONE_'); \/\/ \ud83d\udc48 g \u3092\u3064\u3051\u308b<\/pre>\n\u3053\u308c\u3067\u5b9f\u884c\u3059\u308b\u3068text2<\/code>\u306f\u3001\u300c_ONE_23_ONE_23_ONE_23<\/strong>\u300d\u3068\u306a\u308a\u307e\u3059\u3002<\/p>\n\u3010\u30cf\u30de\u30ea\u5ea6\u3011 \ud83d\ude2b\ud83d\ude2b<\/p>\n
\u968e\u5c64\u304c\u6df1\u3044\u30c7\u30fc\u30bf\u306eif\u6587\u306f\u3001\u6ce8\u610f\u304c\u5fc5\u8981<\/h1>\n
\u4f8b\u3048\u3070\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u3044\u304f\u3064\u304b\u30c7\u30fc\u30bf\u304c\u5165\u3063\u3066\u3044\u3066\u3001\u305d\u306e\u4e2d\u8eab\u306e\u5024\u3092if\u6587<\/code>\u3067\u6bd4\u8f03\u3059\u308b\u5834\u5408\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\nconst item = {\r\n name: '\u5546\u54c1\u540d',\r\n price: 1000\r\n};\r\n\r\nif(item.name !== '')<\/strong> {\r\n\r\n \/\/\r\n\r\n}<\/pre>\n\u5b9f\u306f\u3053\u306e\u5834\u5408\u3067\u306f\u3001\u4f55\u3082\u554f\u984c\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n
\u3057\u304b\u3057\u3001\u554f\u984c\u3068\u306a\u308b\u30d1\u30bf\u30fc\u30f3\u304c\u3042\u308a\u307e\u3059\u3002
\n\u305d\u308c\u306f\u3001null<\/code>\u3084undefined<\/code>\u304c\u5165\u3063\u3066\u304f\u308b\u53ef\u80fd\u6027\u304c\u3042\u308b\u5834\u5408\u3067\u3059\u3002<\/p>\n\u3064\u307e\u308a\u3001\u3082\u3057\u4ee5\u4e0b\u306e\u3088\u3046\u306bitem<\/code>\u306b\u521d\u671f\u5024\u3067null<\/code>\u304c\u5165\u3063\u3066\u3044\u305f\u3068\u3057\u3066\u3001\u305d\u306e\u5f8c\u3082\u30c7\u30fc\u30bf\u304c\u5909\u66f4\u306b\u306a\u3089\u306a\u304b\u3063\u305f\u5834\u5408\u3067\u3059\u3002<\/p>\nlet item = null;<\/strong>\r\n\r\n\/\/ \u305d\u3057\u3066\u3001item \u306e\u30c7\u30fc\u30bf\u304c\u898b\u3064\u304b\u3089\u306a\u304b\u3063\u305f\u3089\u30fb\u30fb\u30fb\r\n\r\nif(item.name !== '')<\/strong> { \/\/ \u3053\u3053\u306f\u30a8\u30e9\u30fc\u306b\u306a\u308a\u307e\u3059\r\n\r\n \/\/\r\n\r\n}<\/pre>\n\u3053\u306e\u5834\u5408\u3001\u300cUncaught TypeError: Cannot read property ‘name’ of null<\/strong>\u300d\u3068\u3044\u3046\u30a8\u30e9\u30fc\u304c\u51fa\u307e\u3059\u3002<\/p>\n\u3064\u307e\u308a\u3001\u300cnull<\/code>\u306b\u306f\u3001name<\/code>\u3068\u3044\u3046\u30d7\u30ed\u30d1\u30c6\u30a3\u306f\u306a\u3044\u3088\u30fb\u30fb\u30fb\ud83d\ude2b\u300d\u3068\u8a00\u308f\u308c\u308b\u308f\u3051\u3067\u3059\u3002<\/p>\n\u305d\u306e\u305f\u3081\u3001\u3053\u3046\u3044\u3063\u305f\u5834\u5408\u3067\u306f\u6b21\u306e\u3088\u3046\u306bif\u6587<\/code>\u306e\u6761\u4ef6\u3092\u3072\u3068\u3064\u5897\u3084\u3057\u3066\u4fdd\u967a\u3092\u304b\u3051\u3066\u304a\u304f\u3053\u3068\u3092\u304a\u3059\u3059\u3081\u3057\u307e\u3059\u3002<\/p>\nif(item && item.name !== '') {<\/strong> \/\/ \u3053\u3063\u3061\u304c\u30d9\u30bf\u30fc\r\n\r\n \/\/\r\n\r\n}<\/pre>\n\u3053\u308c\u306f\u3001\uff11\u3064\u76ee\u306eitem<\/code>\u3067\u5024\u304cnull<\/code>\u3084undefined<\/code>\u306e\u5834\u5408\u306f\u305d\u3053\u3067\u6bd4\u8f03\u304c\u7d42\u4e86\u3059\u308b<\/strong>\u305f\u3081\u3001\uff12\u3064\u76ee\u306eitem.name<\/code>\u307e\u3067\u884c\u304b\u305a\u3001\u7d50\u679c\u3068\u3057\u3066\u30a8\u30e9\u30fc\u306f\u51fa\u306a\u3044\u3068\u3044\u3046\u3053\u3068\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n\u3010\u30cf\u30de\u30ea\u5ea6\u3011 \ud83d\ude2b\ud83d\ude2b\ud83d\ude2b<\/p>\n
sort()\u306f\u5148\u982d\u306e\u6587\u5b57\u304b\u3089\u4e26\u3079\u66ff\u3048\u3092\u3059\u308b<\/h1>\n
\u4f8b\u3048\u3070\u3001\u3044\u304f\u3064\u304b\u306e\u6570\u5b57\u304c\u5165\u3063\u305f\u914d\u5217\u304c\u3042\u3063\u3066\u3001\u305d\u306e\u6570\u5b57\u3092sort()<\/code>\u3067\u4e26\u3079\u66ff\u3048\u308b\u5834\u5408\u306f\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n\u5b9f\u969b\u306e\u4f8b\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
\/\/ \u26a0\u3053\u308c\u306f\u9593\u9055\u3063\u305f\u4f8b\u3067\u3059<\/strong>\r\n\r\nconst numbers = [1, 3, 11, 8, 13];\r\nconst sortedNumbers = numbers.sort()<\/strong>; \/\/ \ud83d\udc48 \u6570\u5b57\u306e\u9806\u306b\u306f\u306a\u3089\u306a\u3044<\/pre>\n\u7d50\u679c\u3068\u3057\u3066sortedNumbers<\/code>\u306f\u6b21\u306e\u3088\u3046\u306b\u4e26\u3079\u66ff\u3048\u3089\u308c\u308b\u3053\u3068\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n[1, 11, 13, 3, 8] <\/strong>\/\/ \ud83d\udc48 \u601d\u3063\u3066\u305f\u306e\u3068\u9055\u3046\u30fb\u30fb\u30fb<\/pre>\n
![\"\"](\"https:\/\/blog.capilano-fw.com\/wp-content\/uploads\/2019\/08\/no_3.png\")
\u300c\u306f\u3058\u3081\u3066\u77e5\u3063\u305f\u3068\u304d\u306f\u3001\u3053\u3046\u306a\u308a\u307e\u3057\u305f\uff08\u7b11\uff09\ud83d\udc46\u300d<\/p>\n